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Brand New Concord Furnace Doesn't Work In Cold Weather

I purchased a 90% efficient condensating Concord furnace, model number 95G1UH090CP16 in mid-October of this year with a Honeywell programmable thermostat. When it was installed in October, the weather was mild (in the 50s) and the furnace worked great. However, now that it's December and has gotten quite cold in New England, the furnace is on the fritz despite being brand new. The plumber who installed it (and another guy from the same company) has been out to try to fix it, and cannot figure out what's wrong with it - an HVAC repair guy from a different company was out, and cannot figure out what's wrong with it. The plumber called Concord Tech Support, and they couldn't figure out what was wrong with it - but I haven't had heat for 2 weeks despite temps below freezing, and I have a 1 year old son, so I'm getting a little desperate here. Here's what I know:

- There is 18 feet of piping and 4 elbows (5 elbows allowed with up to 19 feet of piping, so we're below that)
- Everything is properly pitched toward the furnace
- The drain piping etc appears to be installed correctly, and drains into a condensate pump that appears to be functioning properly
- There are no clogs/debris in the intake or exhaust pipes. There is no soot/dirt clogging any parts, it's only been in use for a month and a half
- By all appearances, there is nothing wrong with this furnace except for the fact that it doesn't work

The symptoms:
- If the temps outside are mild, the furnace works fine and keeps my house at the set temperature with no issues. If it gets cold, the following happens:
- Fan turns on, burners ignite, everything works properly for anywhere from 30 secs-3 mins. Then everything shuts down, blower turns on. It doesn't get nearly warm enough to get the house up to temp, but everything turns on and appears to be running properly while it's running
- Sometimes a pressure switch error that indicates the pressure switch trips while the inducer is open (3 blinks) gets thrown. Other times, it's just a solid light, indicating no problem at all (even tho there clearly is one)
- There is water getting into the inducer fan. I do not know where it's coming from. According to the Concord tech support guys, it's not possible. He said the only reason for water in the inducer fan is that the furnace is double trapped (it's not - we did have the drain pipe in the hole of the condensate pump, but it has since been moved to make absolutely sure it's not touching the water when it rises)
- The furnace doesn't drain while it's running, but I believe it should... It drains after the burners go out and everything shuts down
- There is no lock out; if I set the thermostat high (in the mid-70s or 80s) the furnace will kick on and off every half hour or so, but it only runs for a little bit before going out. If I turn the temp down on the thermostat until the request for heat turns off and then turn it back up so the request for heat comes back, it turns the furnace on - I do not need to manually turn power on and off to the furnace, the thermostat does its job, but the furnace only runs for a little while each time
- It is not a thermostat issue, as jumping the wires doesn't solve the problem
- The pressure switch appears to be operating properly, as does the sail switch and the rest of the furnace. There's clearly a drainage issue due to the water in the inducer, but everything appears to be installed properly and the condensate pump is working - also, if it wasn't hooked up properly, it wouldn't work fine in warmer weather

I'm not even looking to DIY this, but I'm not sure what to do at this point - 2 plumbers, an HVAC guy, and the Concord tech support dudes are stumped, and I'm frickin freezing. I have a brand new furnace and no heat - the place I bought it from has a guy who's Concord certified, but he's on vacation for another week (of course). Does anyone maybe have ANY insight that I can pass along to the pros as to what could possibly be wrong with this furnace? Thanks in advance.

The plumber who installed it (and another guy from the same company) has been out to try to fix it, and cannot figure out what's wrong with it..

That may be your entire problem right there.

Time to time you get a bad: furnace, coil, condenser. If that happens you usually swap it out and get it running.

A few weeks ago I had an issue with something and I had to call support, still could not get it to run, so they sent out their troubleshooter and found the issue and got it up and running.

If all is accurate, and if your installer is licensed to do HVAC work, you should be able to ask your installer to contact Concord and have them send out thier troubleshooting Specialist, they should be more than happy to do that.

I would have them look at the install manual and make sure condensate hoses and pressure switch hoses are correct, is the furnace an up flow vertical, horizontal or downflow? I acually am having an exact same issue on a furnace now that someone installed incorrectly 10 years ago and they have had many issues. Maybe some pictures would help.

The first thing that came to mind when reading your description of the problem is it may be tripping the high temperature limit, could be poor ducting. Pictures would be helpful. It probably doesn't run long enough in mild weather to trip the limit before satisfying the tstat. Make certain the drain piping is EXACTLY the way the installation manual says it should be for whatever position the furnace is installed in.

Do this : email this guy with this information. Removed E-mail ...... he is their head tech troubleshooter and a good friend of mine. See if you can arrange for a good smart tech hvac guy (not a plumber, sorry) to be there and have him call in to tech support to talk to Kyle at a pre determined time. Kyle is in Columbia SC, so he is in EST. Also take notice of the flashing lights that indicate what the problem is...take note of the # of flashes, make notes. Try to have the install manual handy.

The drain instructions are very specific .... is there a TEE in the drain? perhaps all should be unhooked and re-done. IF the furnace is going out on limit, the flashing lights will indicate that. These are very good products, something is being missed unless there could be something partially plugged inside the unit. Good Luck!

Concord furnaces are made by AlliedAir, a subsidiary of Lennox (www dot alliedair dot com -- we are not supposed to put Email addy's on the forum for technical reason). Your furnace came from the Lennox plant in Marshallatown Iowa. Myself and Bob above are AlliedAir dealers in South.

I second what Bob said, contact tech support at AlliedAir , ask for Kyle. Tell Kyle Bob or John sent you.

A few weeks ago I had an issue with something and I had to call support, still could not get it to run, so they sent out their troubleshooter and found the issue and got it up and running.

The plumber did call Concord, and they won't send anyone out directly - they did train/certify someone from the supply house we purchased the furnace from to be a Concord tech, but that guy is on vacation for a week right now unfortunately. So we're in a holding pattern, and we're going on the 3rd week without heat :/ I'm hoping we can get SOMEONE to come out - will be on the Concord rep's ass all day!

Joe, they've been studying the manual and think that all the hoses etc are correct - if they weren't correct, would the furnace run properly in mild weather? It's definitely something to do with the weather dropping below freezing - if it's 50 outside, everything runs great. It's a vertical/horizontal furnace, but we have it installed vertically - I believe it is an upflow (the exhaust and intake pipes are installed at the top and drainage pipes on the left side). I'm not at home now (can't hang there with the baby, it's 54 degrees) but will try to snap some pics this evening. There's really not much to see tho, you can't actually see the water. Is it possible that there's a problem with an airlock in the collection box? It doesn't seem to drain until AFTER the furnace shuts off, at which point you can turn it on again (but it only runs for a little bit, not long enough to get anything warm).

jtrammel - Drain piping seems to be ok, but it's always possible - however, I don't think it's reaching a max temp, because it's only burning for 30 seconds to 3 minutes. It's running longer in the warmer months to get the house up to temp than it is now, because it's shutting off WAY before it's up to temp in the cold months - is it possible that it could be overheating in as little as 45 seconds of burner time?

bha - the email addy was removed! Can you add spaces, or spell out the AT instead of writing it like an email addy? I'd love to reach out to him. I don't think there's anything plugged in there - it's so new that I can't imagine what could have gotten into it, and all the pipes and tubes seem to be clear. But it's always possible that something was hooked up improperly - sometimes the LED isn't throwing an error at all (just a solid light indicating that everything is running well) and sometimes it blinks 3 times indicating a pressure switch error with inducer open. Do either you (ga) or bob have the Allied Air tech support number handy? I have the number for my region's sales director - but I'll do some Googling and see if I can track Kyle down in the meantime. Cross your fingers... Thanks for your help, guys!

Most of us in the heating and AC world know that installation is more important than product or price. This sounds like what myself and endless professionals see: Someone bought a replacement furnace (or system) based on price rather than qualifications... now it does not work when the weather is extreme (extreme hot or extreme cold).

I have been to the manufacturing plants of many heat and AC co's and I can tell you from PERSONAL experience; AlliedAir makes good products and their quality control is one of the highest in the industry. I might also add one of the biggest names in the industry also has the highest number of warranty claims... a choo-choo...

I really am sorry you are having issues, nothing is perfect. Give Tech support a call, ask for Kyle, have the stuff noted available.

Nevermind, brain fart... We've been calling the Allied Air tech support line - not sure if we've spoken to Kyle or someone else. So we have that number I'll call back and see if I can reach Kyle directly - the guy we talked to last nite couldn't figure it out, said he'd never heard of the symptoms we're having, and referred us to the supply house where we bought it (who has a certified Concord tech, who is on vacation this week). I'll post some pics this evening and you guys can see if it looks right to you - we're thinking that since it's not draining until after everything shuts down, maybe the inducer fan is creating a vacuum in the collection box and preventing the water from the secondary heat exchanger from draining until the fan goes off and the vacuum is broken - does that sound at all possible to you?

Joe, they've been studying the manual and think that all the hoses etc are correct - if they weren't correct, would the furnace run properly in mild weather? It's definitely something to do with the weather dropping below freezing - if it's 50 outside, everything runs great. It's a vertical/horizontal furnace, but we have it installed vertically - I believe it is an upflow (the exhaust and intake pipes are installed at the top and drainage pipes on the left side). I'm not at home now (can't hang there with the baby, it's 54 degrees) but will try to snap some pics this evening. There's really not much to see tho, you can't actually see the water. Is it possible that there's a problem with an airlock in the collection box? It doesn't seem to drain until AFTER the furnace shuts off, at which point you can turn it on again (but it only runs for a little bit, not long enough to get anything warm).

jtrammel - Drain piping seems to be ok, but it's always possible - however, I don't think it's reaching a max temp, because it's only burning for 30 seconds to 3 minutes. It's running longer in the warmer months to get the house up to temp than it is now, because it's shutting off WAY before it's up to temp in the cold months - is it possible that it could be overheating in as little as 45 seconds of burner time?

bha - the email addy was removed! Can you add spaces, or spell out the AT instead of writing it like an email addy? I'd love to reach out to him. I don't think there's anything plugged in there - it's so new that I can't imagine what could have gotten into it, and all the pipes and tubes seem to be clear. But it's always possible that something was hooked up improperly - sometimes the LED isn't throwing an error at all (just a solid light indicating that everything is running well) and sometimes it blinks 3 times indicating a pressure switch error with inducer open. Do either you (ga) or bob have the Allied Air tech support number handy? I have the number for my region's sales director - but I'll do some Googling and see if I can track Kyle down in the meantime. Cross your fingers... Thanks for your help, guys!

You are on the right thinking track in your first paragraph above. A condensing furnace (like yours) should make literally gallons of water every night when it is freezing outside... it can make as much as a pint in that 3-4 minutes before shutdown.

Go back through your entire furnace drain system... think of the simple reality water runs downhill... Yeah, I now that may sound condescending... not meant to. There is something impeding that downhill flow of water, causing the safeties to shut down the furnace.

Send us the picture... lots of pictures...

Tell you what: I may get in trouble with the forum mgt... however a cold baby is not a good thing; Click on my screen name and send me an Email.

Ga is correct, the colder is gets the more it condenses, it sounds like an air Locked drain from improper installation, I literally just seen this happen yesterday. I temporarily fixed it until I get the part the installed left out. At the very least they should be able pipe the hoses in a bucket to keep you and your baby warm.

If all else fails, sometimes you have to try repalcing the control board. I'd lean that way because it's shutting down at times without throwing a fault. That shouldn't be possible unless the call for heating ends.

Maybe try running it using indoor combusiton air. Where it is located? IF in a basement you coudl insert just a short 2' peice of pipe wiht 1 elbow for the combustion air inlet. IF its' a closet, jsut leave the closet door open so it has plenty of air.

Actually...taking a tep back, is only hte exhaust vented outdoors? OR are both piped outdoors? We definietly need photos. You might have a a negative pressure indoors near the unit. Could be caused by even stack effect expecially if you have a firepalce chimney that's not sealed or lots of upstairs air leaks. the 1st floor can become slightly negative. Add in a marginal piping (you said it was only 1' "in reserve" for the vent length.